Elisa Pre-processing Optimization And Evaluation Of Sulfonamides Residuals And Its Application In Meat Drug Residues Detection

Sulfonamides are used for prevention of animal disease and promotion of animal growth,and their excessive residuals in animal muscles,milk and eggs will greatly damage human health.Strict maximum limit standards are established for sulfonamides in animal derived food such as meat across the nations,and effective and practical monitoring plays an important role in guaranteeing food safety,where efficient and accurate monitoring technique is quite essential.In current standards,the pre-processing extraction effects in samples by the Homogeneous Extraction-Enzyme Linked Immunosorbent Assay(HE-ELISA)and the Shaking Extraction-Enzyme Linked Immunosorbent Assay(SE-ELISA)need to be improved in order to satisfy the need from the primary port laboratories better.Compared to the previous two assays from the standards,the ultrasonic extraction method has broad application perspective in the field of pre-processing in food monitoring samples for its high extraction efficiency.In this study,the extraction process for monitoring sulfonamides by Ultrasonic Extraction-Enzyme Linked Immunosorbent Aassay(UE-ELISA)is optimized and its methodological evaluation as well as verification is applied for fast monitoring and analysis on sulfonamides residuals in market-sale pork,beef and chicken samples.The main research results in this study are as follows:1.The extraction condition of monitoring sulfonamides residuals in pork by UE-ELISA is optimized by orthogonal experiment under the evaluation index of adding standard recovery.It is shown that the extraction efficiency of sulfonamides residuals in pork reaches the maximum value under the condition that ultrasonic power is 150 W,ultrasonic duration is 10 min and ultrasonic temperature is 20oC,where the average recovery is 92.76%.2.Methodological evaluation is applied on SE-ELISA,HE-ELISA and UE-ELISA,and UE-ELISA is verified by Liquid Chromatography-tandem Mass Spectrometry(LC/MS-MS).Is is shown that the coefficients of variation for all three assays are below 10%,which meets the monitoring specifications.Compared to the other two fast monitoring assays,the limit of detection and limit of quantitation of UE-ELISA are reduced to 0.45 μg/kg and 0.52μg/kg respectively and its recovery range reaches 89.07%-94.94%,which indicates high sensitivity,precision and accuracy of UE-ELISA.The precision and accuracy of UE-ELISA are further verified by LC/MS-MS,and it is shown that the coefficient of variation of LC/MS-MS as well as UE-ELISA is below 5% which indicates numerical reliability.The measured value and adding standard recovery of samples by LC/MS-MS are in accordance with UE-ELISA,where no false-negative/positive results are shown.3.Monitoring and analysis for sulfonamides residuals are carried out on 100 pork samples,50 beef samples and 50 chicken samples by UE-ELISA.The detection rate of sulfonamides residuals in pork samples,beef samples and chicken samples purchased from market are 41.00%,26.00% and 52.00%.The detection range of sulfonamides residuals is5.17 μg/kg-71.96 μg/kg,which is below the maximum residual limit of 100 ug/kg in the state standard.